In a typical wireless network utilizing a coordination function for coordinating transmissions among wireless stations, such a coordination function may be implemented in one of the wireless stations such as a wireless access point (AP) functioning as a coordinator. The wireless stations may communicate via directional transmissions using sector antennas and beam-forming antenna arrays. The coordinator may use omnidirectional transmissions for broadcasts to all wireless stations in all directions (e.g., 360 degrees range).
Alternatively, the coordinator may use quasi-omnidirectional transmissions for broadcasts to a wide range, but not necessarily in all directions. In many wireless area networks (WLANs) such as those according to IEEE 802.11 standards, a coordinator is used in infrastructure mode for providing contention-free access to a wireless communication medium to support Quality of Service (QoS) for certain applications.